Electrochromic Properties of Lithium-Doped Tungsten Oxide Prepared by Electron Beam Evaporation

In this study, xLi2O-(1−x)WO3 powders were mixed with WO3 and Li2O and pressed into target pellets to fabricate electrochromic films on indium tin oxide (ITO) glasses prepared by electron beam evaporation under the parameters of room temperature, and thicknesses of about 530 nm. It was expected that the amount of charge stored in the electrochromic devices (ECDs) could be enhanced by using the doping method in the cathode materials. The experimental results show that as the composition of Li0.18W0.82O2.6 powder was formed, the optimal characteristics of ECD can be obtained. In which, as a voltage of 3.5 V was applied on ECD, a transmittance change (ΔT%) of 53.1%, an optical density (ΔOD) of 0.502, an intercalation charge (Q) of 12.9 mC/cm2 and a coloration efficiency (η) of 41.6 cm2/C at a wavelength of 550 nm can be achieved. These results demonstrate that Li2O doping in WO3 films could effectively improve the coloration and electrochromic properties of ECD devices.